First record of the tinfoil barb Barbonymus schwanenfeldii (Bleeker, 1853) (Cyprinidae) from the wet zone of Sri Lanka

The Tinfoil Barb (Barbonymus schwanenfeldii Bleeker, 1853) is a cyprinid fish native to Southeast Asia that has established feral populations in several regions worldwide. In Sri Lanka, its known distribution has until now been restricted to the Mahaweli River basin in the dry zone. This study reports the first record of this species from the wet zone of the country, specifically from Mawak Oya, a tributary of the Kalu Ganga river basin. The species was initially recorded among artisanal fish catches from this area in October 2024.  Interviews with local fishermen indicate that the species has been present in the area for approximately one year, and its introduction is most likely attributable to escapes from aquaculture facilities or the ornamental fish trade. Given its rapid breeding, ecological adaptability, and previously documented negative impacts on native fish assemblages, the establishment of B. schwanenfeldii in the wet zone of Sri Lanka raises serious concern for the region's rich endemic freshwater ichthyofauna. These findings underscore the urgent need for further studies on its current and potential distribution, ecological impacts, and the development of effective management strategies to mitigate the potential threats posed by this invasive species.